From the looks of it Stellar Dawn could quite possibly have just been an idea for a new name? Or one of the proposed original names for the upcoming game (registered in Jan 2009).
Why do I think this?

If you look at the highlight in the picture above, the renewal date for the domain Stellar Dawn is January 28, 2010. Now of course Jagex probably has auto-renewal enabled, but It makes me ponder than if this was the planned name for game that they would have Extended it much further, such as "www.runescape.com" that has been registered since 2000 and they extended it until 2013. Surely enough they would have extended it by now, is my thought.
Just something to think about, and yes I could be completely over analyzing it, I am not a pro researcher like Ren
What are all of your thoughts, discuss.